1. Field of the Invention
The present invention relates to a filter for preparations used to mount specimens such as cells on a glass slide, and a method of making and using same.
2. Prior art
In medical diagnosis, conventionally cells or their reaggregate are sampled from human bodies for the purpose of performing, for example, cytological diagnosis of cancer, subjected to a staining treatment and then mounted on a glass slide with a sealing medium and a glass cover to make a preparation for microscopic observation. In such an observation, a filter is widely used to separate specimens for making preparations.
Typically, conventional preparations are made as shown in FIGS. 6(a) to 6(c). According to the conventional procedure shown in FIGS. 6(a) to 6(c), specimens (WP) are mounted on a filter (FT) which has been applied to the under surface of a frame (FR) of a filter assembly (F) by means of an adhesive having less bearable property to solvents such as xylene, with foreign materials separated or removed therefrom using a suction or pressurizing means to only leave the specimens on the filter (FT). The specimen are fixed thereon by means of an alcohol to prevent their release from the filter (FT). The specimens (WP) are then stained with desirable color for a specific observation in a stain bath (not shown), impregnated with an organic solvent such as xylene to fix them completely on the filter and set on a glass slide (SG) as shown in FIG. 6(a). As described above, an adhesive having less bearable property to solvents is used to bond the frame (FR) and the filter (FT) to facilitate their separation in the subsequent step, where xylene, for example, actually loosens their bond. Under such a condition, it is easy to remove the frame (FR) and leave the specimens and the filter (FT) on the glass slide (SG) when an extended part (FT) of the filter (FT) is picked up with a pair of pincettes (PS) in the arrow direction shown III in FIG. 6(b). An adequate amount of sealing medium (SM) is then added dropwise over the specimens (WP) which is covered with a cover glass (CG), as shown in FIG. 6(c), to complete a preparation (P).
As only the specimens (WP) are secured on the filter (FT), it is possible to carry out microscopic observations accurately and safely without any specific skill even when conventional preparations are used. However there exists, problems inherent in such preparations which should be solved.
The first disadvantage is that the adhesive having less bearable property to solvents such as xylene is often dissolved unexpectedly in the stain to cause a premature separation of the frame (FR) and the filter (FT) during the staining treatment step and that it is still necessary to use xylene, for example, to loosen their bond.
Secondarily, the specimens (WP) along with the filter (FT) are often irregularly strained when the extended part (ft) of the filter (FT) is picked up to separate the frame (FR) and the filter (FT), which tends to result in imprecise observations.
Further, as the frame (FR) and the filter (FT) are adhered to each other over relatively wider area, the behavior of the sealing medium on the filter (FT) is not uniform, i.e., its behavior around the specimens (WP) is quite different from that in the other areas of the filter (FT). This might result in a serious inconvenience upon microscopic observations because of a deflection caused by such ununiformity of the sealing medium on the filter (FT).
It has been required by those who are engaged in cytological diagnosis to develop a filter which enables easier making of preparations without contamination of their fingers due to the sealing medium seepage or the like.